REACTION NETWORKS IN CATALYTIC HYDRODENITROGENATION

The catalytic hydrodenitrogenation of some nitrogen containing heterocyclic compounds, typical of those found in residual petroleum fractions and coal liquids, has been studied. In all cases examined, the reaction is a stepwise process with hydrogénation of the nitrogen containing ring as the first step. The hydrodenitrogenation of indole was studied in some detail to obtain more extensive information concerning the nature of subsequent steps. The reaction was found to proceed via the intermediates, 2,3-dihydroindole and o-ethylaniline. The predominant subsequent reaction path leads to formation of ethylcyclohexane via ring hydrogenation and ammonia elimination or direct hydrogenolysis. Direct hydrogenolysis of o-ethylaniline to ethylbenzene occurs to a lesser extent. Rate constants for the major steps in the sequence have been estimated. It has been shown that relative rates of the various steps (but not the overall reaction pattern) depend on the catalyst employed. © 1979.